1. Field of the Invention
The present invention relates to the field of forms processing in a data driven system and more particularly to managing an external data model not implemented through a document object model (DOM) accessible application programming interface (API).
2. Description of the Related Art
Form based input is the enabling technology which permits the widespread distribution of applications across generic client platforms such as the conventional content browser. In the prototypical distributed application, a markup language defined interface can form the principal conduit through which end users can interact with backend application logic. Often configured in the form of a Web page, the interface can be provided to the content browser by a content server and can take the form either of a pre-defined static page, or a dynamically generated page. Form input fields can be positioned within the interface through which user input can be accepted and posted to the backend application logic for further processing.
Despite the flexibility afforded by hypertext markup language (HTML) defined forms, HTML defined forms mix data, logic and presentation in contravention of standard programming practices. In this regard, the well-known model-view-controller paradigm demands that each of data, logic presentation remain separable. In this way, though the presentation layer may change to suit the user interface requirements of an end user, the underlying logic layer need not also change. To accommodate the increasing complexity of transactions conducted through forms, the XForms specification has been proposed as a presentation independent way of handling interactive Web transactions. Significantly, the XForms specification separates data and logic from presentation in that XForms utilizes the extensible markup language (XML) for data transport and HTML for data display.
An XForms processor commonly has been implemented as a specialized DOM parser agent where the XForm is realized as a DOM document. Specifically, the Xforms processing model is defined through the propagation of DOM events. Accordingly, the XForms specification defines a normative binding for uniform resource identifier (URI) accessible data having an XML representation. The normative binding can utilize a standardized hypertext transfer protocol (HTTP) URI scheme. Thus, the XForms specification presupposes the use of an external data model which is implemented according to a DOM accessible API.
Notwithstanding, trends in data driven computing have embraced a data model which has not been implemented according to a DOM accessible API. Specifically, service data objects (SDO) provide a framework for data application development, which includes an architecture and API. SDO supports compound data objects as a graph of data objects which incorporate a change history for each node of the graph. In this regard, SDO client modifications of the data graph are reflected in an internal change summary data structure. In operation, upon submission of a modified SDO graph, a data mediator service propagates the changes specified by the change summary to the ultimate data source.
It will be apparent to the skilled artisan that SDO simplifies the data programming model in object oriented computing and abstracts data in a service oriented architecture (SOA). SDO further unifies data application development and supports and integrates XML. Thus, SDO provides an advanced and able data model for supporting enterprise class data driven applications. Yet, SDO does not implement a DOM accessible API. Accordingly, enterprise class data driven applications cannot fully exploit the XForms processing model.